Brunel X-team

Brunel X-team

An electric motorcycle for the Isle of Man TTXGP competition

BX-09 is Brunel X-team’s entry to the 2009 Time Trials Xtreme Grand Prix (TTXGP), the first zero emissions motorcycle race. It is held alongside the prestigious Tourist Trophy (TT) at the Isle of Man circuit. Consisting of 1 lap of the 37.73 mile Mountain Course, the race pushes the limits of emerging technologies and provides the perfect platform to showcase the ideas and innovations of the team.

The team has used a Triumph Daytona 675 donated to them as a donor vehicle for reference and minor ancillaries. Major aspects of the motorcycle have been analysed, redesigned and tested to adhere to the rules of the competition and optimise performance.

Analysis Of The Problem

Being such a unique and notoriously challenging circuit, great importance was placed on track analysis to ensure a complete understanding of the rigors placed upon the bike in terms of power requirements and handling. The maximum velocities, track elevation changes, corner radii and subsequent lean angles were studied at over 300 points around the track. From this a true representation of the course and the required setup of BX-09 has been determined.

Following circuit analysis, an entire “throttle to road” simulation was produced in Mathworks Matlab/Simulink R2008a to precisely calculate the power requirements for the race. Calculations included the effects of rolling resistance, aerodynamic drag and drivetrain losses to best represent the race conditions. From this simulation an ideal power source was identified as well as the optimal battery pack configuration. It also allowed optimisation of the final drive ratios allowing the best compromise of acceleration and maximum velocity.

The distribution of mass and its effect on the stability and handling of BX-09 was considered throughout the design process. Once the chassis geometry was fixed it could be ensured that the centre of mass was optimally placed by careful location of the powertrain so as not to greatly differ from the original donor bike. It was also made sure that the ability of the front and rear suspension and maximum lean angle of the bike were not impinged upon. Design and Creation of BX-09

One of the biggest challenges of this project was to house the lithium-ion cells required to get the bike around the course at a competitive speed. Drawing upon the findings of the vehicle dynamics study, cells were located in specific areas so that the centre of gravity, and mass distribution, was kept similar to that of the original Daytona 675.

When using an electric powertrain, there is a heavy dependence upon the control systems to ensure that not only the powertrain operates optimally, but also to make riding the bike as close to a conventional motorcycle as possible. Therefore, it has been a key design criterion of BX-09 to incorporate as much adjustability and tuning into the control system as possible.

The flexibility afforded by the Agni motor’s power characteristics allows use of a single gear direct drive output. This is run from the motor through a bespoke AP Racing clutch to allow complete disconnection of drive to the rear wheel in the event of a powertrain failure. Special attention was paid to improving the overall performance of the standard Agni motor through lightweighting and advanced tuning.

BX-09 Specifications

Drivetrain

- Agni Motor - Bespoke AP Dry Single Plate Clutch - 520E Chain Upgrade - Adjustable Gearing Ratio

Power Source

- LiFebatt Lithium-ion XPS Prototype Cells - 72 V, 480 A System

Top Speed 100 mph + 0-60 mph 4 seconds Torque 60Nm Mass 220 kg